CONFIG_MACH_M28EVK is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_M28EVK.
Result is shown for kernelversion 5.3.7

Support DENX M28EVK Platform

modulename: mach-m28evk.ko

configname: CONFIG_MACH_M28EVK

Linux Kernel Configuration
└─>Support DENX M28EVK Platform
In linux kernel since version 3.3 (release Date: 2012-03-18)  
source code: